If $x \boxdot y = 8y+4$ and $x \bigtriangleup y = 3x^{2}-y^{2}$, find $(0 \bigtriangleup -4) \boxdot 3$.
Explanation: We don't need to find $0 \bigtriangleup -4$ because $x \boxdot y$ depends only on the right operand. Find $x \boxdot 3$ $ x \boxdot 3 = (8)(3)+4$ $ \hphantom{x \boxdot 3} = 28$.